Why Retro Pay Isn't Just Paying the Difference

The overtime part is what gets missed

If a raise should have started three weeks ago, the first instinct is simple: pay the missing rate difference for the hours already worked.

That is enough only when the affected period had no overtime.

If the employee worked overtime during that period, the old overtime rate was wrong too. You owe the straight-time difference for the affected hours, plus the extra half-time difference for the overtime hours.

That small extra step matters. Miss it and the unpaid amount becomes unpaid overtime, not just an ordinary payroll adjustment.

A quick example

An employee was paid $20/hour, but should have been paid $22/hour. During the affected period, they worked 180 total hours, including 20 overtime hours.

• Straight-time correction: $2 x 180 = $360
• Overtime correction: 0.5 x $2 x 20 = $20
• Total retro pay: $380

If you pay only $360, the employee is still short $20.

How to fix it cleanly

• Pull the effective date for the corrected rate.
• Pull the affected workweeks, not just the total hours.
• Count overtime hours inside those workweeks.
• Pay the straight-time difference and the overtime difference.
• Keep the calculation, payment date, and source records together.

If the employee already left, or if the correction involves Massachusetts, California, bonuses, commissions, or multiple employees, slow down before you run payroll. Those are the situations where a small retro-pay fix can pick up state penalties or a bigger overtime calculation.

Fix the source, not just the check

The cheapest correction is usually the one you catch quickly, pay fully, and document clearly. But the better fix is upstream: make sure the rate, effective date, bonus setup, or time rule that caused the error is corrected before the next payroll run.